Merge "Switch to the new kernel API for obtaining fault address tag bits." (2a9da2ae) · Commits · e / os / android_system_core

debuggerd/crash_dump.cpp

+1 −4

Original line number	Diff line number	Diff line
		@@ -299,11 +299,8 @@ static void ReadCrashInfo(unique_fd& fd, siginfo_t* siginfo,
		process_info->abort_msg_address = crash_info->data.s.abort_msg_address;
		*siginfo = crash_info->data.s.siginfo;
		if (signal_has_si_addr(siginfo)) {
		// Make a copy of the ucontext field because otherwise it is not aligned enough (due to
		// being in a packed struct) and clang complains about that.
		ucontext_t ucontext = crash_info->data.s.ucontext;
		process_info->has_fault_address = true;
		process_info->fault_address = get_fault_address(siginfo, &ucontext);
		process_info->fault_address = reinterpret_cast<uintptr_t>(siginfo->si_addr);
		}
		regs->reset(unwindstack::Regs::CreateFromUcontext(unwindstack::Regs::CurrentArch(),
		&crash_info->data.s.ucontext));

debuggerd/handler/debuggerd_handler.cpp

+9 −4

Original line number	Diff line number	Diff line
		@@ -167,7 +167,7 @@ static bool get_main_thread_name(char* buf, size_t len) {
		* mutex is being held, so we don't want to use any libc functions that
		* could allocate memory or hold a lock.
		*/
		static void log_signal_summary(const siginfo_t* info, const ucontext_t* ucontext) {
		static void log_signal_summary(const siginfo_t* info) {
		char thread_name[MAX_TASK_NAME_LEN + 1]; // one more for termination
		if (prctl(PR_GET_NAME, reinterpret_cast<unsigned long>(thread_name), 0, 0, 0) != 0) {
		strcpy(thread_name, "<name unknown>");
		@@ -186,8 +186,7 @@ static void log_signal_summary(const siginfo_t* info, const ucontext_t* ucontext
		// Many signals don't have an address or sender.
		char addr_desc[32] = ""; // ", fault addr 0x1234"
		if (signal_has_si_addr(info)) {
		async_safe_format_buffer(addr_desc, sizeof(addr_desc), ", fault addr %p",
		reinterpret_cast<void*>(get_fault_address(info, ucontext)));
		async_safe_format_buffer(addr_desc, sizeof(addr_desc), ", fault addr %p", info->si_addr);
		}
		pid_t self_pid = __getpid();
		char sender_desc[32] = {}; // " from pid 1234, uid 666"
		@@ -544,7 +543,7 @@ static void debuggerd_signal_handler(int signal_number, siginfo_t* info, void* c
		return;
		}

		log_signal_summary(info, ucontext);
		log_signal_summary(info);

		debugger_thread_info thread_info = {
		.crashing_tid = __gettid(),
		@@ -638,5 +637,11 @@ void debuggerd_init(debuggerd_callbacks_t* callbacks) {

		// Use the alternate signal stack if available so we can catch stack overflows.
		action.sa_flags \|= SA_ONSTACK;

		#define SA_EXPOSE_TAGBITS 0x00000800
		// Request that the kernel set tag bits in the fault address. This is necessary for diagnosing MTE
		// faults.
		action.sa_flags \|= SA_EXPOSE_TAGBITS;

		debuggerd_register_handlers(&action);
		}

debuggerd/libdebuggerd/include/libdebuggerd/utility.h

+0 −2

Original line number	Diff line number	Diff line
		@@ -91,6 +91,4 @@ void get_signal_sender(char* buf, size_t n, const siginfo_t*);
		const char* get_signame(const siginfo_t*);
		const char* get_sigcode(const siginfo_t*);

		uintptr_t get_fault_address(const siginfo_t* siginfo, const ucontext_t* ucontext);

		#endif // _DEBUGGERD_UTILITY_H

debuggerd/libdebuggerd/utility.cpp

+0 −37

Original line number	Diff line number	Diff line
		@@ -451,40 +451,3 @@ void log_backtrace(log_t* log, unwindstack::Unwinder* unwinder, const char* pref
		_LOG(log, logtype::BACKTRACE, "%s%s\n", prefix, unwinder->FormatFrame(i).c_str());
		}
		}

		#if defined(__aarch64__)
		#define FAR_MAGIC 0x46415201

		struct far_context {
		struct _aarch64_ctx head;
		__u64 far;
		};
		#endif

		uintptr_t get_fault_address(const siginfo_t* siginfo, const ucontext_t* ucontext) {
		(void)ucontext;
		#if defined(__aarch64__)
		// This relies on a kernel patch:
		// https://patchwork.kernel.org/patch/11435077/
		// that hasn't been accepted into the kernel yet. TODO(pcc): Update this to
		// use the official interface once it lands.
		auto* begin = reinterpret_cast<const char*>(ucontext->uc_mcontext.__reserved);
		auto* end = begin + sizeof(ucontext->uc_mcontext.__reserved);
		auto* ptr = begin;
		while (1) {
		auto* ctx = reinterpret_cast<const _aarch64_ctx*>(ptr);
		if (ctx->magic == 0) {
		break;
		}
		if (ctx->magic == FAR_MAGIC) {
		auto* far_ctx = reinterpret_cast<const far_context*>(ctx);
		return far_ctx->far;
		}
		ptr += ctx->size;
		if (ctx->size % sizeof(void*) != 0 \|\| ptr < begin \|\| ptr >= end) {
		break;
		}
		}
		#endif
		return reinterpret_cast<uintptr_t>(siginfo->si_addr);
		}